/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */

package org.netbeans.modules.parsing.spi.support;

import org.netbeans.api.annotations.common.NonNull;
import org.netbeans.modules.parsing.impl.TaskProcessor;
import org.netbeans.modules.parsing.spi.SchedulerTask;
import org.openide.util.Parameters;

/**
 * Provides a thread safe testing of the {@link SchedulerTask} canceling.
 * <p class="nonnormative">
 * Recommended usage:
 * <pre>
 * {@code
 * public class MyTask extends ParserResultTask {
 *     private final CancelSupport cancel = CancelSupport.create(this);
 *
 *     public void run (T result, SchedulerEvent event) {
 *         ...
 *         if (cancel.isCancelled()) {
 *             return;
 *         }
 *         ...
 *     }
 * }
 * }
 * </pre>
 * @since 1.74
 * @author Tomas Zezula
 */
public final class CancelSupport {
    
    private final SchedulerTask owner;

    private CancelSupport(@NonNull final SchedulerTask owner) {
        Parameters.notNull("owner", owner); //NOI18N
        this.owner = owner;
    }


    /**
     * Returns true if the owning task was canceled.
     * @return true when the owning task was canceled.
     */
    public boolean isCancelled () {
        return TaskProcessor.isCancelled(owner);
    }

    /**
     * Creates a new instance of the {@link CancelSupport}.
     * @param owner the owning {@link SchedulerTask}
     * @return the newly created {@link CancelSupport}
     */
    @NonNull
    public static CancelSupport create(@NonNull final SchedulerTask owner) {
        return new CancelSupport(owner);

    }
}
